[postgis-devel] MultiPoint weirdness

[strk at refractions.net]

On Tue, Jan 18, 2005 at 02:24:49PM +0100, Markus Schaber wrote:
> Hi, strk,
> 
> strk at refractions.net schrieb:
> 
> > Mmm.. I've checked it. Actually no holes there, previous behaviour
> > was strict-standard.
> >
> > Valid constructs:
> >
> > 	POINT EMPTY
> > 	LINESTRING EMPTY
> > 	POLYGON EMPTY
> > 	MULTIPOINT EMPTY
> > 	MULTILINESTRING EMPTY
> > 	MULTIPOLYGON EMPTY
> > 	GEOMETRYCOLLECTION EMPTY
> >
> > Our old GEOMETRYCOLLECTION(EMPTY) was NON-standard... maybe we should
> > *only* allow GEOMETRYCOLLECITON(EMPTY) and all the other standard ones ?
> >
> > REF: 99-049 -- 3.2.5.2 Language Constructs
> 
> Is it shure that the old code did not emit other empty geometries? If
> yes, I think it is best to allow all standard formats, and keep
> GEOMETRYCOLLECITON(EMPTY) as a backwards compatibility special case.

Committed. All standard constructs accepted
plus GEOMETRYCOLLECTION(EMPTY)

> 
> But this raises another question: Is it okay to collapse all emtpy
> geometries into a GEOMETRYCOLLECTION, as both your and my code behave
> currently?

Yeah, that's what I've been thinking...

We might have all 7 types of empty geoms, considering also
dimensionalities. 
Should we have an EMPTY 3DM LINESTRING and an EMPTY 4D POINT ?
Would they equals() ?

This is not likely to go in 1.0, but worth discussing.

--strk;

> 
> Thanks,
> Markus



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